Onic acids

Notice that the carboxyl group that stays behind during the decarboxylation of mal onic acid has a hydroxyl function that is not directly involved m the process Compounds that have substituents other than hydroxyl groups at this position undergo an analogous decarboxylation... 

Derivatives of aldoses in which the terminal aldehyde function is oxidized to a carboxylic acid are called aldonic acids. Aldonic acids are named by replacing the -ose ending of the aldose by -onic acid. Oxidation of aldoses with bromine is the most commonly used method for the preparation of aldonic acids and involves the furanose or pyranose form of the carbohydrate. 

The catalyst is a cobalt carbonyl that is prepared in situ from cobaltous hydroxide, and nonylpyridine is the promotor. Oxidation of the aldehyde produces 3-hydroxypropionic acid. 1,3-Propanediol and 3-hydroxypropi-onic acid could also be produced from acrolein (Chaper 8). ... 

Fast sulphon black F ( C.I.26990). This dyestuff is the sodium salt of 1-hydroxy-8-( 2-hydroxynaphthylazo) -2- (sulphonaphthylazo) -3,6-disulph onic acid. The colour reaction seems virtually specific for copper ions. In ammoniacal solution it forms complexes with only copper and nickel the presence of ammonia or pyridine is required for colour formation. In the direct titration of copper in ammoniacal solution the colour change at the end point is from magenta or [depending upon the concentration of copper(II) ions] pale blue to bright green. The indicator action with nickel is poor. Metal ions, such as those of Cd, Pb, Ni, Zn, Ca, and Ba, may be titrated using this indicator by the prior addition of a reasonable excess of standard copper(II) solution. 

Interesting regioselectivities have been known for more than 100 years for azo coupling reactions with aminonaphthol derivatives such as 6-amino-4-hydroxy-2-naphthalenesulfonic acid (12.136, y-acid), 7-amino-4-hydroxy-2-naphthalenesulf-onic acid (J-acid), and 4-amino-5-hydroxy-2,7-naphthalenedisulfonic acid (H-acid). They give two types of isomeric azo compounds depending on the pH-value of the... 

Organic Fluorides. Part IX. The Formation and Resolution of a-Hydroxy-a-trifluoromethylpropi-onic Acid, R. A. Darrall, F. Smith, M. Stacey, and J. C. Tatlow, /. Chem. Soc., (1951) 2329-2332. 

Aldonic acids are divided into aldotrionic acid, aldotetronic acids, aldopentonic acids, aldohexonic acids, etc., according to the number of carbon atoms in the chain. The names of individual compounds of this type are formed by replacing the ending -ose of the systematic or trivial name of the aldose by -onic acid . 

Salts are named by changing the ending -onic acid to -onate , denoting the anion. If the counter ion is known, it is given before the aldonate name. 

In contrast, when excess amounts of the HHTs derived from simple aliphatic glycinate esters, such as 25, were used in excess in reactions with diaryl phosphites (SO), the related glyphosate aminals containing aryl phosphonate esters 46 were isolated in low yield (5-15%). Like many aminals, these triesters 46 were acid-sensitive and were quantitatively converted to the corresponding triester strong acid salts 47 upon treatment with either HCl or methanesulf onic acid (27). 

The deconqxjsiticm of pn onic acid was inhibited by the presence of acetic add and the inhibition beJiavior was approximated by purely non-comprtitive inhibition model as given by following equation. 

Although widely used, colorimetric methods for determining total ur-onic acid and hexosamine are now regarded as providing, at best, only semi-quantitative estimates of heparin.42 Colorimetric reactions in a strong acid, such as the carbazole reaction for the uronic acids48 and the Morgan-Elson reaction for the hexosamines,49 are not specific for hepa-... 

Acids that are used in addition to trifluoroacetic acid include trifluoroacetic acid with added sulfuric acid203 or boron trifluoride etherate,210,211 perfluorobu-tyric acid,212 hydrogen chloride/aluminum chloride,136,146,213 perchloric acid in chloroform,214 p-loluenesull onic acid alone134 or with aluminum bromide or aluminum chloride,192 concentrated sulfuric acid in two-phase systems with dichloromethane, alcohol, or ether solvents,209,215 trifluoromethanesulfonic acid,216 chlorodifluoroacetic acid,134 and the monohydrate of boron trifluoride... 

An exception is reported when the reactions are conducted using a twofold excess of dichloroethylsilane with equal equivalents of either aluminum chloride or aluminum bromide and /Moluenesull onic acid at 40° for two hours in dichloromethane. Under these conditions, 1-methylcyclohexene affords methylcyclohexane in 65-75% yield, whereas cyclohexene gives cyclohexane in 17-23% yield.192... 

Toyo No. 50 Descending for 9 hrs 2% p-toluene sulph-onic acid in water saturated n-butanol 0.11- 0.20 0.23 )Separation )of neamine )from neo-)mycins B 204... 

The use of tartrates as chiral auxiliaries in asymmetric reactions of allenyl bor-onic acid was first reported by Haruta et al.69 in 1982. However, it was not for several years that Roush et al.,70 after extensive study, achieved excellent results in the asymmetric aldol reactions induced by a new class of tartrate ester based allyl boronates. 

The bromodeoxyaldonolactones have been used for the preparation of aminodeoxy aldonic acids and aminodeoxy sugars via azido derivatives (45,46). Likewise, a- and /J-aminopolyhydroxy acids have been prepared by treatment of the bromodeoxyaldonolactones with liquid ammonia (47). Thus, 3-amino-3-deoxy-D-threonic acid and 3-amino-3-deoxy-D-arabin-onic acid (40b) were obtained from 2-bromo-2-deoxy-L-threono- or D-xy-lono-1,4-lactone (38). It was shown that 2,3-epoxy carboxamides (namely, 39) are intermediates of the reaction. Heating at 90° for long periods led to the 3-amino-3-deoxyaldonamides, which upon acid hydrolysis yielded the corresponding aldonic acids. 

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